This invention refers to a bogie for a railway platform car. In the manufacturing of bogies of the type used for railway vehicles there are known bogies in which the central part between the wheels is lower than the axis of rotation of the wheels themselves (as for example described in the Italian industrial utility model patent No. 195367 on behalf of the same Applicant), so as to enable the production of the platform cars. In order to be motor-driven these bogies obviously require independent motors for each wheel since it is not possible to connect the wheels on both sides by means of an axle.
So as not to encumber the space between the wheels and thus keep it as free as possible for the internal volume of the vehicle it is necessary to position the motors to the side of the bogie.
In bogies of known technique however there are numerous problems. For example, in several known embodiments the sides of the bogie are excessively high and consequently these bogies can only be used inside revolving couplings in articulated vehicles since otherwise the bogie is unable to turn to describe a curve. Another problem is the structural complexity and/or difficult maintenance due also to the very close and interdependent disposition of the various parts, which makes them difficult to be reached and to be removed. In known bogies of the aforesaid type there are also various other problems concerning their shock absorbing functions which are essential for travelling comfort. For example, in order to decrease the dimensions, bogies have been designed in which each traction motor is rigidly mounted on the wheel which in turn is interconnected to the rest of the bogie with interposition of shock absorbers. Although this solution offers a certain reduction in the dimensions, it is extremely disadvantageous in terms of comfort due to the considerable mass rigidly connected to the wheel.
Moreover, due to the intense vibrations transmitted to the motor the lifespan of the latter is considerably shortened.
For these reasons, a bogie made in this way gives rather poor results even in low-speed vehicles, such as urban public transport vehicles, and is totally unserviceable in relatively high-speed vehicles, such as railway vehicles. The general scope of this invention is to obviate the aforementioned problems by providing a bogie with independently driven wheels for the construction of railway platform cars, which is of limited dimensions, easy to construct and to service, suitable both for low and for high-speed uses and ensuring smooth, comfortable running.